Note: Descriptions are shown in the official language in which they were submitted.
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23940-495
The present invention relates to a new dosage device intended to
be used for dosing of micronized or granulated substances or
microcapsules ~hereinafter referred to collectively as particulate
material) and containing pharmacologically active substances.
Several preparations of drugs are nowadays administered in
micronized or granulated form or in the form of microcapsules.
These substances are filled into capsules of hard gelatine, which
are intended for oral administration and are swallowed whole by
the patient. Children and adults who have difficulties in
swallowing a whole capsule are recommended to open the capsule and
spread the contents on a suitable piece of food and to swallow.
It is, however, difficult to open the capsule and pour out the
contents without any loss of the substance. Capsules of hard
gelatine are an expensive, but effective, way to administer
pharmacologically active substances to patients, who are able to
swallow the capsules unbroken. It is, however, not sensible to
use this expensive way of dispensing into capsules of hard
gelatine, when the patient later on, with some difficulty, opens
the capsule and pours out the contents.
It has previously been proposed to provide dosage devices to
enable the particulate material to be dispensed accurately. For
example DE-A-2 052 051 describes a dosage device comprising an
operating unit and a storage chamber. The operating unit is
fitted relatively loosely to the casing of the device.
Substances having small particles thus easily fall on the sliding
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surfaces between the two relatively movable units, so that
substance being fed jams. With such a dosage device, which does
not have a feediny under force it is difficult to dose small
amounts of micronized or granulated substances with an accuracy
which is sufficient for the dispensing of drugs.
According to the present invention there is provided in a device
for releasing a dosage of a particulate medication that includes:
a dosage dispensing unit having a face ~ith a plurality of
recesses therein adapted to receive and meter a reproducible
amount of said medication, a storage chamber adapted to contain
the medication and having a face thereon and an outlet opening on
said face which is mounted in slidable, abutting relation to the
face of said dispensing unit, and a dispensing tube having a first
open end through which medication can be discharged and a second
open end mounted in slidable abutting relation to the face of said
dispensing unit, the improvement wherein (1) said dispensing unit
is mounted for rotation around an axis, and said recesses, the
outlet opening of said storage chamber and the second end of said
dispensing tube are all disposed in relation to said axis, such
that, upon rotation of said dispensing unit, said recesses are
rotated successively between operative engagement with the outlet
opening of said storage chamber fox reception of medication and
operative engagement with the second end of said dispensing tube
for discharge of medication, (2) there is a resilient scraper
located in the outlet opening of the storage chamber in sliding,
resilient contact with the face of said dispensing unlt and
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23940-495
configured and disposed relative to the axis of rotatlon such that
it first pushes medication into the recess and then removes excess
medication from above said recesses during rotation of said
dispensing unit and insure that each recess contains a
reproducible amount of medication, (3) said dispensing unit has
ratchet means thereon arranged around the axis on which said unit
rotates, (4) said device has ratchet engaging means mounted for
rotation around the axis on whlch said dispensing unit rotates,
said ratchet engaging means being in slidable spring-loaded
contact with said ratchet means, (5) said ratchet means and
ratchet engaging means are adapted to cooperate with each other
such that rotation of said engaging means in one rotational
direction will cause said dispensing unit to rotate in the same
direction to a plurality of stations wherein at each station at
least one of the recesses in said dispensing unit is in mating
relation to the outlet opening in said storage chamber and another
of said recesses is in mating relation to the second end of said
dispensing tube and such that said engaging means will release
from said ratchet means as the ratchet engaging means is rotated
in the opposite rotational direction, and (6) the device has stop
means coacting between the ratchet engaging means and the storage
chamber for stoping the dispensing unit at each station and
preventing it from advancing to the next station until the ratchet
means has been released, the ratchet engaging means has been
rotated in said opposite rotational direction, and the ratchet
means corresponding to the next station has been engaged.
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With the construction according to the present invention, the
substance is prevented from getting into contact with the sliding
surfaces in the two relatively movable parts of the dosage device
and in this way feeding of each dose can be achieved wlthout any
problems. In the dosage device according to the invention, the
scrapers make it possible to fill the recesses in the dosing unit
in an accurately reproducible way. A high dosage accuracy can
thus be obtained by the rotation of the dosing unit.
In order that the invention may more readily be understood, the
following description is given, merely by way of example,
reference being made to the accompanying drawing, in which:
Figure 1 is an axial cross-section of one embodiment of dosage
device according to the invention, and
Figure 2 is a cross-section taken along the line II-II of Figure
1.
The dosage device of the present invention, is preferably produced
in plastic and can be considered to comprise four separate units
as follows:
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an operating unit 1 at the bottom of the dosage device;
a spring loaded dosing unit 2;
a scraping unit 3; and
a storage chamber 4 provided with a dispensing channel 5 for
the dose to be dispensed.
A further separate part is shown in the drawings and is preferred.
but is not essential, this being in the form of a plastic or metal
hood 6 which can be retained by a peripheral rib (not shown) at
the upper part of the operating unit 1. This rib enables the hood
to be removably retained. An alternative way of sealing the device
is to provide a plug in the top of the dispensing channel 5.
At the lower mid part of the storage chamber 4, the scraping unit
3 is fixed to the inner wall of the storage chamber so that it cannot
rotate relative thereto. The scraping unit in fact includes the
lower part of the dispensing channel 5 which is formed integrally
with the storage chamber 4. From Figure 2 it will be seen more clearly
that the scraping unit 3 includes 5 radially extending arms each
of which carries a resilient scraper 8 in sliding contact with the
upper surface of the dosing unit 2 which, in turn, is provided with
six circumferentially spaced slightly frustoconical recesses 7
positioned immediately under the scrapers 8. In order to guide for
rotation of the dosing unit 2, the scraping unit has an outer peripheral
skirt engaging the cylindrical outer surface of the dosing unit
2 and a short inner annulus engaging the upper surface of the dosing
unit inwardly of the recesses 7 in order to prevent jamming at feeding.
The dosing unit 2 is loaded by a spring 9 in order to press the
dosing unit against the scraping unit. Between the dosing unit,
which has a toothed ring 13, and the spring there is situated a
disc 14 which is keyed to the storage chamber. The operating unit
1, against which the other end of the spring 9 abuts, carries a
resilient arm 12 which is engageable with the toothed ring 13. Thus
the disc 14, in effect, controls the angular movement of the operating
unit 1 and the dosing unit 2 so that one of the recesses 7 will
always stop in the correct position that is immediately below the
dispensing channel 5 as shown in Figure 1. Furthermore, the disc
14 reduces the friction between the spring and the dosing unit.
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In the operating unit 1 there is provided a space 10, as illustrated
closed by a porous pad and into the space 10 can be inserted a drying
agent such as silica gel in order to protect the contents of the
device from the humidity of the air. The ingress of humidity will
S also be reduced by the provision of the hood 6.
The particulate pharmaceutically active substance is stored inside
the storage chamber 4 and the actual dosing operation is carried
out with the dosing device in the upright position shown in Figure
1, by rotating the operating unit at first clockwise and then counter-
clockwise. The ratchet mechanism formed by the toothed ring 13 and
the resilient arm 12 will thus index the dosing unit so that first
one and then another recess appear immediately under the dispensing
channel. All of the recesses passes successively the storage chamber
and can be filled with the particulate material therein. Thus, a
predetermined amount of particulate pharmaceutically active substance
can be dosed by the correct choice of the size of the recess 7.
The effect of the scrapers 8 on the scraping unit 3 is firstly to
force and pack the particulate material into the recesses and secondly
accurately to level off the particulate material at the top of the
recesses. This means that when a recess 7 arrives immediately below
the dispensing channel 5 it will be completely and accurately filled.
All that is then necessary is to turn the dosage device upside down
and the particulate material will flow down the dispensing channel
5. By choosing the size of the recess for which ever substance is
to be dispensed, one can thus choose the size of a dose which may
for example be varied within wide limits, say from 1 to 5 mg or
5 to 200 mg. The number of recesses in the dosing unit may vary
depending on different factors, such as the amount of active substance
which should be administered in each dose, the physical properties
of the active substances and so on. In a preferred embodiment, the
dosing unit has six recesses and these recesses are preferably
cylindrical or preferably frustoconical as shown and should preferably
hold 1 dose of active substance.
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The size of the storage chamber may be chosen to suit the requirements
expected for a particu1ar active substance. In the dosage device
the chamber may, for example, contain sufficient active substance
for about 100 doses. The dosage device has an opening for filling
or refilling of active substance in the upper part of the storage
chamber. The opening is preferably sealed by a plastic plug 11.
In an alternative embodiment the dosage device has a resilient key
which makes it possible to feed the device with one hand. Each push
on the key causes indexing of the dosing device so that a recess
filled with the active substance is placed in communication with
the dispensing channel.
The dosage device may be used as container and aid in dispensing
1~ of a great number of active substances such as enprophylline,
theophylline and terbutaline.
The best mode of carrying out the invention known at present is
illustrated in Figure 1.
Example
In order to demonstrate the dosage accuracy of the dosage device
according to the present invention the following tests have been
carried out with different dosing units with different sizes of
the recesses A-G. The container was filled with Theo-Dur~ Sprinkle
A~ substance (which is a slow release microencapsulated preparation
of theophylline) mixed with 1 and 2% of talcum respectively. When
the dosage accuracy of 500 doses was established a maximum deviation
of 3.5% was obtained. Cf. the table below.
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Test with seven different dosage units containing
Theo-Dur Sprinkle substance mixed with talcum
.
The figures below are the average values of 500 doses from each
dosage device.
_ __
Dosage ¦ Talcum
unit '
~ 1% 2%
I mg/dose Srel %mg/dose Srel %
, ,
A ,104.1 2.15 2.1104.2 2.45 2.4
B 94.0 2.36 2.594.0 2.66 2.8
C ,85.4 2.29 2.784.8 2.30 2.7
D ,73.2 2.45 3.375.1 1.73 2.3
E 64.7 1.68 2.664.5 2.02 3.1
F ~54.3 1.33 2.553.4 1.87 3.5
G 145.8 1.34 2.945.9 1.30 2.8
As a comparison reference is made to Pharm. Nord, which specifies
that 90% of the capsules shall have a weight which does not deviate
more than 10% from the stipulated weight. The rest shall not deviate
more than 20%. With the new dosage device according to the invention
these requirements are thus met with an ample margin.
